New species of Baetidae (Ephemeroptera) from the Upper River Sigi,Usambara, Tanzania

Additional species of mayflies are described from the relatively well-studied fauna of the Upper River Sigi in the East Usambara Mountains of Tanzania. They comprise Cheleocloeon sigiense sp. n. and Centroptiloides ornatus sp. n. A species of Afroptiloides, of which only the adult is known, is figured but not named. The composition of the assemblage of genera known as the Bugilliesia complex is critically examined.